Buttons on BSP page not triggering OnInputProcessing

Hi experts,

can anyone tell me what would cause the buttons on a BSP page to suddenly stop working.

We've recently performed an ECC6 upgrade and Unicode conversion and during the testing phase certain BSP's seem to suffer from this issue. To resolve this I deactivated and then reactivated the service in transaction SICF. However, the issue keeps coming back and I don't understand why.

Thanks in advance,

Chris